Reversible pump turbines



1965 M. BRAIKEVITCH ETAL 3,

REVERSIBLE PUMP TURBINES Filed 001;. 29, 1963 4 Sheets-Sheet l 28, 1955 M. BRAIKEVITCH ETAL 3,226,033

REVERS IBLE PUMP TURBINES 4 Sheets-Sheet 2 Filed Oct. 29, 1363 8, 1965 M. BRAIKEVITCH ETAL 3,225,083

REVERSIBLE PUMP TURBINES Filed Oct. 29, 1965 4 Sheets-Sheet 3 8, 1965 M. BRAIKEVITCH ETAL 3,226,083

REVERS IBLE PUMP TURBINES 4 Sheets-Sheet 4 Filed Oct. 29, 1963 United States Patent Ofiiice 3,226,083 Patented Dec. 28, 1965 3,226,083 REVERSIBLE PUMP TURBINES Michael Braikevitch and James Gavin Warnock, Netherton, England, assignors to The English Electric Company Limited, London, England, a British company Filed Oct. 29, 1963, Ser. No. 319,773 Claims priority, application Great Britain, Apr. 5, 1961, 12,185/ 61 8 Claims. (Cl. 253-26) This application is a continuation-in-part of our application Serial No. 181,675 lodged March 22, 1962 and now abandoned.

The present invention relates to reversible pump turbines.

According to this invention, a reversible pump turbine comprises a runner having a hub and vanes mounted thereon and defining working fluid passages, stator structure co-operating with said runner and including an inlet/ delivery casing, a draft tube, and passage means between said inlet/delivery casing and said working fluid passages, said runner and stator structure being capable of operation as a turbine when the runner is driven in one direction of rotation by the flow of working fluid through the working fluid passages from the inlet/delivery casing to the draft tube, and being also capable of operation as a pump when rotation of said runner in the other direction causes the flow of working fluid through the working fluid passages from the draft tube to the inlet/delivery casing, blading means on said runner, and means selectively to supply working fluid to said blading means to drive said runner in said other direction.

Further features and objects of the invention will be apparent from the following description of two embodiments, which refers to the accompanying drawings, of which:

FIGS. 13 show a first embodiment of reversible pump turbine during different phases of operation, and

FIG. 4 shows a second embodiment of reversible pump turbine in accordance with the invention.

Referring to FIGS. l-3, a reversible pump turbine comprises a runner 11 mounted in stator structure generally shown at 12.

The runner comprises a hub, in the form of a crown 13, connected by vanes 14 to a skirt 15, so as to define working fluid passages, and is connected to a shaft 16 which in turn is connected to a motor generator 17.

The stator structure comprises a spiral inlet/delivery casing 18 which is connected to the penstock (not shown) of the reversible pump turbine, which in turn is connected to a large reservoir of water.

The spiral casing has a ring of vanes 19 mounted at its inner periphery, and the stator structure also defines passages between the spiral casing 18 and the working fluid passages of the runner. It includes built-up structure 20 connecting the spiral casing to a draft tube 21, which exhausts to a large reservoir of water at a lower level. The stator structure also includes built-up structure 22 joining the upper parts of the spiral casing 18 and forming a housing around the shaft 16. A ring of adjustable guide vanes 23 is mounted directly inward of the ring of vanes 19 and can be adjusted to vary the flow area of the passages.

Each of the guide vanes 23 is mounted on a spindle 24 to be rotatable about the axis of the spindle, and the chord of the guide vanes is at least equal to the spacing between adjacent vanes so that the guide vanes can be rotated to a position in which the leading edge of one vane seals against the trailing edge of the adjacent vane, substantially closing the passages between the ring of vanes 19 and the runner 11. The guide vanes thus form closure means in the passages leading from the spiral casing to the runner; they have upper and lower shrouds.

The angular position of the guide vanes 23 is adjusted simultaneously by rotation of a ring 25 connected to lever arms 26 on spindles 24 through links 27.

Seals are provided between the runner 11 and the stator casing 12, including rotating seal elements 28, 29 cooperating with stationary seal elements 30, 31 respectively.

The structure so far described can operate either as a pump or as a turbine, the runner rotating in one direction as a pump and in the reverse direction as a turbine. The guide vanes 23 are arranged so that even in their fully open position, corresponding to operation of the pump or turbine at full speed, they each lie in a plane at an angle to the radial plane through the axis of rotation of the runner 11, thus imparting a circumferential component to the flow of water during turbine operation, or receiving water delivered by the runner with a circumferential component in pump operation.

During turbine operation, water from the upper reservoir passes from the spiral casing through the ring of vanes 19 and guide vanes 23 and drives the runner in one direction of rotation, causing the motor generator 17 to generate power which may be fed to the grid. In operation as a pump the mot-or generator 17 acts as a motor, receiving power from a suitable source such as the grid, and drives the runner in the opposite direction of rotation to pump water from the draft tube 21 through the guide vanes 23 and into the spiral casing 18 and thus via the penstock to the upper reservoir.

There are a number of ways of achieving the transition from turbine operation to pump operation; e.g. this may be achieved by closing the guide vanes 23 so that the runner, being immersed in water, slows down from the synchronous speed in the turbine direction to zero speed and then supplying power to the motor generator to exert a torque on the shaft so that the runner accelerates to the synchronous speed in the pumping direction. It will be appreciated that this would require a large current, as also would bringing the runner to synchronous speed in the pumping direction when starting from rest.

The reversible pump turbine in accordance with the present invention is provided with an auxiliary turbine coupled to the runner 11 and arranged so that when water is supplied from the upper reservoir to the auxiliary turbine the latter exerts a torque on the runner to drive it in the pumping direction of rotation.

The auxiliary turbine in this embodiment comprises blading means in the form of blades 33 joining two parts of the crown 13, and is fed with water from the spiral casing, through vanes 35, through vertical passages in which the spindles 24 pass, and through passages 36 defined by walls of the stationary structure 22 and leading to the inlet of the blades 33. The passages 36 are not radial, but have a circumferential component, so that water is delivered to blades 33 with a circumferential component in the sense to drive the runner in the pumping direction. A valve 37 is provided surrounding the inlet of the blades 33 and connected through rods 38 to pistons 39 working in cylinders 40. Pressure fluid is supplied to the cylinders 40 by pipes 41, 42, the supply of fluid through pipes 41 causing the valve 37 to be opened and through pipe 42 causing the valve 37 to be closed.

The auxiliary turbine exhausts to a space within the crown 13 of the runner, which is closed when the auxiliary turbine is not in operation by a conical cover 44 shaped to form a continuation of the lower surface of the crown 13. The conical cover is connected by a rod 45 to a piston 46 in a cylinder 47 coaxial with the shaft 1 6, and pipes 48, 49 are connected to the two ends of the cylinder 47 to convey pressure fluid to them. The supply of pressure fluid through pipe 48 to the space below piston 46 causes the conical cover 44 to be retracted upward as shown in the drawings so that its lower surface forms a continuation of the upper surface of the passage containing blades 33, and the supply of pressure fluid to the space above piston 46 causes the cover 44 to be extended.

A pipe 50 is connected from a supply of compressed air to the draft tube 21, for the supply of air to the runner as will be described.

In operation, when the runner 11 is rotating in the turbine direction, the adjustable guide vanes 23 are normally open, the valve 37 shut and the cover 44 extended, as shown in FIG. 1.

When it is required to change from turbine to pump operation, the adjustable guide vanes 23 are rotated to the closed posit-ion, as shown in FIG. 2, and the motor generator is disconnected from the grid system before the runner falls below synchronous speed. The conical cover 44 is retracted and the valve 37 is opened to allow water from the spiral casing 18 to flow through blades 33 to exert a torque on the runner 11 in the pumping direction of rotation.

Compressed air may be supplied through pipe 50 to the draft tube, expelling any remaining water down the draft tube, but the invention allows the runner to be brought rapidly up to speed in the pumping direction while rotating in water.

The runner decelerates to zero rotational speed, reverses its direction of rotation, and is accelerated in the pumping direction by the fl-ow of water through the auxiliary turbine.

When synchronous speed in the pumping direction is reached, if the water has been expelled the supply of compressed air through pipe 50 is cut off, and the water readmitted up the draft tube 21 until the runner 11 is rotating in water with the adjust-able guide vanes still closed. The motor generator 17 is connected with the grid and synchronized, and may then be placed on load as a motor.

The valve 37 is then gradually closed and the cover '44 extended, so that the driving power is gradually supplied by the motor generator instead of by the auxiliary turbine, and the adjustable guide vanes 23 are then rotated to the open position, when the reversible pump turbine operates as a pump, in the configuration shown in FIG. 3.

The ring gate valve 37 can be replaced by a series of individual valves, of any convenient type, or by a single valve in a duct leading from the spiral casing or from the penstock to the auxiliary turbine.

To reduce losses when the ring gate valve 37 and the cover 44 are both closed, the space between them may be filled with com-pressed air through pipe 51 which enters the space within the crown 13 through drillings 52 in the shaft coupling flange, causing water to flow out through drain pipe 53.

Referring now to FIG. 4, the reversible pump turbine shown is generally similar to that of FIGS. 1-3 and corresponding parts may be identified by the reference numerals. However, in this embodiment the auxiliary turine is formed outside the skirt 115 of the runner 111. The blades 133 of the auxiliary turbine are fed from the spiral casing 118 through passages formed with vanes 135, which have a circumferential component. Adjacent the inlet is provided a valve 137 connected through rods 138 to pistons 139 in cylinders 140. Instead of the exhaust from the auxiliary turbine passing int-o the draft tube 121, as in FIGS. 1-3, it flows into a separate duct 154 provided with a valve 155. The duct 154 may be drained of water by means of a drain pipe 153 and compressed air supply 151 each controlled by appropriate valves.

The centre of the crown 113 is completed by a fairing 144flx-edtoit. t

The operation of this embodiment is exactly the same as of that described with reference to FIGS. 1-3, adjustable guide vanes 123 corresponding with guide vanes 23, valve 137 with valve 37, and valve with movable cover 44.

What we claim as our invention and: desire to'secure by Letters Patent is: t

1. A reversible pump turbine comprising a runner having a hub and vanes mounted thereon and defining working fluid passages, stator structure co-operating with said runner and including an inlet/delivery casing, a draft tube, and passage means between said inlet/ delivery casing and said working fluid passages, said runner and stator structure operating as a turbine when the runner is driven in one direction of rotation by the flow of working fluid through the Working fluid passages from the inlet/ delivery casing to the draft tube, and operating as a pump when rotation of said runner in the other direction causes the flow of working fluid through the working fluid passages from the draft tube to the inlet/ delivery casing, blading means on said runner, and means selectively to supply working fluids to said blading means to drive said runner in said other direction.

2. A reversible pump turbine comprising a runner having a hub and vanes mounted thereon and defining working fluid passages, stator structure co-operating with said runner and including an inlet/ delivery casing, a draft tube, and first passage means between said inlet/delivery casing and said working fluid passages, closure means in said first passage means and movable between an open position in which said inlet/delivery casing communicates freely with said working fluid passages and a closed position in which communication between said inlet/delivery casing and said working fluid passages is cut off, said runner and stator structure being capable of operation as a turbine when the runner is driven in one direction of rotation by the flow of working fluid through the working fluid passages from the inlet/delivery casing to the draft tube, and being also capable of operation as a pump when rotation of said runner in the other direction causes the flow of working fluid through the working fluid passages from the draft tube to the inlet/delivery casing, blading means on said runner, second passage means between said blading means and said inlet/delivery casing, and valve means operable independently of said closure means in said second passage means movable between a closed position in which said blading means is cut off from said inlet/delivery casing and an open position in which said blading means communicates through said second passage means with said inlet/delivery casing whereby working fluid is supplied to said blading means to drive said runner in said other direction.

3. A reversible pump turbine comprising a runner having a crown, a skirt, a plurality of vanes interconnecting said crown and said skirt and defining working fluid passages, stator structure co-operating with said runner and including an inlet/ delivery casing, a draft tube, and first passage means between said inlet/ delivery casing and said working fluid passages, closure means in said first passage means and movable between an open position in which said inlet/delivery casing communicates freely with said working fluid passages and a closed position in which communication between said inlet/delivery casing and said working fluid passages is cut off, said runner and stator structure operating as a turbine when the runner is driven in one direction of rotation by the flow of working fluid through the working fluid passages from the inlet/ delivery casing to the draft tube, and operating as a pump when rotation of said runner in the other direction causes the flow of working fluid through the working fluid passages from the draft tube to the inlet/ delivery casing, blading means formed in said crown, second passage means between said blading means and said inlet/ delivery casing, and valve means in said second passage means movable between a closed position in which said blading means is cut off from said inlet/delivery casing and an open position in which said blading means communicates through said second passage means with said inlet/delivery casing whereby working fluid is supplied to said blading means to drive said runner in said other direction.

4. A reversible pump turbine comprising a runner having a crown, a skirt, a plurality of vanes interconnecting said crown and said skirt and defining working fluid passages, stator structure co-operating with said runner and including an inlet/ delivery casing, a draft tube, and first passage means between said inlet/ delivery casing and said working fluid passages, closure means in said first passage means and movable between an open position in which said inlet/delivery casing communicates freely with said working fluid passages and a closed position in which communication between said inlet/ delivery casing and said working-fluid passages is cut off, said runner and stator structure operating as a turbine when the runner is driven in one direction of rotation by the flow of working fluid through the working fluid passages from the inlet/ delivery casing to the draft tube, and operating as a pump when rotation of said runner in the other direction causes the flow of working fluid through the working fluid passages from the draft tube to the inlet/delivery casing, blading means formed on said skirt, second passage means connecting said blading means and said inlet/ delivery casing, and valve means in said second passage means movable between a closed position in which said blading means is cut off from said inlet/delivery casing and an open position in which said blading means communicates through said second passage means with said inlet/ delivery casing whereby working fluid is supplied from said inlet/ delivery casing to said blading means to drive said runner in said other direction.

5. A reversible pump turbine comprising a main runner and stator and an auxiliary runner and stator, means for admitting fluid to drive the main runner as a turbine while preventing the flow of fluid to the auxiliary runner, means for closing the flow of fluid to the main runner and opening the flow of fluid to the auxiliary runner to drive the auxiliary runner as a turbine and the main runner in the pumping direction.

6. A device as in claim 5 further including means to stop the flow of fluid to the auxiliary runner and operate the main runner as a pump.

7. A device as in claim 6 further including means for expelling water from the main runner while the speed of the runner is reduced to zero and then rotated in the pumping direction.

8. A device as in claim 7 wherein the means for expelling water comprises a source of compressed air and conduit means for connecting said source to the runner.

References Cited by the Examiner UNITED STATES PATENTS 2,131,611 9/1938 Biggs 103-87 2,671,635 3/1959 Willi 253--117 2,972,469 2/1961 Mayo 25326 X FOREIGN PATENTS 301,411 10/ 1900 France.

389,318 9/1908 France.

466,165 10/ 1928 Germany.

476,207 5/ 1929 Germany. 1,064,439 8/1959 Germany.

DONLEY J. STOCKING, Primary Examiner.

ROBERT M. WALKER, LAURENCE V. EFNER,

Examiners. 

1. A REVERSIBLE PUMP TURBINE COMPRISING A RUNNER HAVING A HUB AND VANES MOUNTED THEREON AND DEFINING WORKING FLUID PASSAGES, STATOR STRUCTURE CO-OPERATING WITH SAID RUNNER AND INCLUDING AN INLET/DELIVERY CASING, A DRAFT TUBE, AND PASSAGE MEANS BETWEEN SAID INLET/DELIVERY CASING AND SAID WORKING FLUID PASSAGES, SAID RUNNER AND STATOR STRUCTURE OPERATING AS A TURBINE WHEN THE RUNNER IS DRIVEN IN ONE DIRECTION OF ROTATION BY THE FLOW OF WORKING FLUID THROUGH THE WORKING FLUID PASSAGE FROM THE INLET/DELIVERY CASING TO THE DRAFT TUBE, AND OPERATING AS A PUMP WHEN ROTATING OF SAID RUNNER IN THE OTHER DIRECTION CAUSES THE FLOW OF WORKING FLUID THROUGH THE WORKING FLUID PASSAGES FROM THE DRAFT TUBE TO THE INLET-DELIVERY CASING, BLADING MEANS ON SAID RUNNER, AND MEANS SELECTIVELY TO SUPPLY WORKING FLUIDS TO SAID BLADING MEANS TO DRIVE SAID RUNNER IN SAID OTHER DIRECTION. 